Bill Cosby, in the midst of a serious PR crisis as accusations about him sexually assaulting women make headlines around the world, has decided to stay silent.

In an interview on NPR’s “Weekend Edition” that aired Saturday (where Cosby and his wife appeared to talk about loaning works to the National Museum of African Art), Cosby, 77, didn’t say a word when host Scott Simon asked him about the allegations. In the past, Cosby has repeatedly denied these claims.

“This question gives me no pleasure, Mr. Cosby, but there have been serious allegations raised about you in recent days,” Simon said, without specifically saying what the allegations in question were.

There’s a long pause. “You’re shaking your head no. I’m in the news business, I have to ask the question: Do you have any response to those charges?” Simon said.

Another long pause. “Shaking your head no,” Simon continued, and said again: “There are people who love you who might like to hear from you about this — I want to give you the chance.” And again, no response. (Listen to the audio here.)

The interview comes a couple days after Cosby’s name quietly disappeared from the “Late Show With David Letterman” guest line-up for next week. Cosby was supposed to appear on the show on Wednesday. Then, late this week, his name was gone and replaced with talk show host Regis Philbin.

There’s no word on whether the cancellation was Cosby’s idea or the show’s. Letterman’s publicist told the Associated Press that “We can’t comment on the guest booking process.”

Considering the way the Cosby camp so blithely promoted a new Twitter game this week (the chance to “meme” Cosby by putting a clever caption under his picture), it’s possible they had no idea how severe the image crisis had become. The “meme” game ended in disaster and was pulled in a matter of hours after Twitter users started posting images like this:

Although Cosby has been accused of sexual assault in the past by

— including in a civil lawsuit settled in 2004 — the story didn’t get much consistent mainstream attention until this fall, when during a stand-up routine, comedian Hannibal Buress called Cosby a rapist.

This point was made by  a first-person article published on Post Everything, a commentary section of The Washington Post Web site, that went viral this week, as actress Barbara Bowman detailed her experience in a first-person account called “Bill Cosby raped me. Why did it take 30 years for people to believe my story?” Bowman wrote that in 1985, Cosby (at that point a star on “The Cosby Show”) offered to be her mentor — then “brainwashed me into viewing him as a father figure, and then assaulted me multiple times. ”

Bowman said she’s told her stories many times (offering to testify in the 2004 civil suit, but it was settled before she had a chance) and no one paid attention until Buress, a man, spoke out.

“I have never received any money from Bill Cosby and have not asked for it. I have nothing to gain by continuing to speak out. He can no longer be charged for his crimes against me because the statute of limitations is long past,” she wrote. “That is also wrong. There should be no time limits on reporting these crimes, and one of my goals is to call for legislation to that end.”

UPDATE, 11/16:

On Sunday morning, Cosby’s lawyer, John P. Schmitt, posted the following statement to Cosby’s Web site:

Over the last several weeks, decade-old, discredited allegations against Mr. Cosby have resurfaced. The fact that they are being repeated does not make them true. Mr. Cosby does not intend to dignify these allegations with any comment. He would like to thank all his fans for the outpouring of support and assure them that, at age 77, he is doing his best work. There will be no further statement from Mr. Cosby or any of his representatives.
Barbara Bowman says she is “certain” Bill Cosby drugged and raped her when she was a teenaged actor in the 1980s. (Erin O'Connor and McKenna Ewen/The Washington Post)